Pressure sores

Overview

•Immobility - most important modifiable risk factor; prevents sensing or responding to pressure

•Risk assessment tools: Waterlow score (UK standard), Braden scale, PURPOSE T - incorporate build, skin type, age, nutrition, continence, mobility, neurological deficit

•Mechanical forces: pressure (capillary occlusion), shear (vessel kinking in deeper tissue), friction (epidermal abrasion)

Classification

Pressure ulcer staging

Stage	Tissue involved	Appearance
Stage 1	Intact skin	Non-blanchable erythema
Stage 2	Partial thickness - dermis	Shallow open ulcer or intact/ruptured blister
Stage 3	Full thickness - subcutaneous tissue	Deep crater; no bone/tendon/muscle visible
Stage 4	Full thickness - exposed bone/tendon/muscle	Possible undermining, sinus tracts, eschar

⚠️

Damage typically begins in deep tissues adjacent to bone and tracks outward - the visible surface wound frequently underestimates true depth. Deep tissue injury can be present with apparently intact skin.

Presentation

•Non-blanchable erythema - earliest sign; unlike reactive hyperaemia (blanches), indicates capillary damage and red cell extravasation

•Pain/discomfort over a pressure area - may be absent in neuropathy or cognitive impairment

•Localised warmth (inflammation) or coolness (ischaemia/necrosis); induration from oedema

•Signs of infection - increasing pain, purulent exudate, surrounding cellulitis, fever, systemic deterioration

•Common sites: sacrum/coccyx, heels, greater trochanters, ischial tuberosities, lateral malleoli, occiput

🎯

In darker skin tones, non-blanchable erythema may not appear as redness - look for localised discolouration, warmth, firmness, or oedema. Missing Stage 1 damage in darker skin is a recognised patient safety issue.

Investigations

•Pressure ulcers are a clinical diagnosis - investigations assess severity, screen for complications, and guide management

🥇 First-line

•FBC and CRP (infection/anaemia), serum albumin (nutritional/healing status), blood glucose/HbA1c (diabetes), wound swab MC&S only if clinical infection present

🏆 Gold standard

•MRI - investigation of choice for suspected osteomyelitis (Stage 3-4 ulcer over bone, failure to heal, systemic sepsis without other source)

🥈 Second-line

•plain X-ray - may show bony destruction in established osteomyelitis but insensitive early

Management

•Pressure relief (cornerstone): reposition at least every 6 hours (at-risk) or every 4 hours (high-risk); pressure-redistributing mattresses and heel offloading devices used proactively

•Wound care: clean with saline; debridement required for Stages 3-4 (autolytic, enzymatic, larval, or sharp/surgical); dressing choice guided by moisture balance, depth, and infection risk

•Nutritional support: dietitian review; oral supplements or enteral feeding if severe; correct micronutrient deficiencies (zinc, vitamin C); ensure adequate hydration

•Infection control: antibiotics not indicated for colonisation alone; if clinical infection confirmed, treat empirically guided by wound swab MC&S; deep infection/osteomyelitis requires prolonged courses and specialist input

•Pain management: regular analgesia plus pre-emptive dosing before dressing changes; WHO analgesic ladder; atraumatic dressings

•Surgical referral: for complex Stages 3-4, osteomyelitis, or extensive necrosis - surgical debridement, negative pressure wound therapy (VAC), or flap reconstruction

Prevention

•Documented risk assessment on admission (Waterlow, Braden, or PURPOSE T) and personalised repositioning plan

•Structured skin assessment on admission and at regular intervals - check all bony prominences

•Pressure-redistributing equipment prescribed proactively; specific heel offloading devices for bed-bound patients

•Moisture management - incontinence pads, barrier creams to prevent maceration

•Nutritional screening (MUST tool) and early dietitian input; patient and carer education

Complications

•Cellulitis - spreading bacterial infection of surrounding skin/subcutaneous tissue

•Osteomyelitis - bone infection underlying Stage 3-4 ulcer; insidious onset, often without florid systemic features; requires MRI and prolonged antibiotic therapy

•Sepsis - haematogenous spread; life-threatening in frail patients

•Sinus tract/fistula formation - deep tissue tracking, may communicate with joints or body cavities

🚨

Suspect osteomyelitis in any Stage 3-4 pressure ulcer over bone that fails to heal despite optimal wound care, or where probe-to-bone testing is positive. MRI is the investigation of choice - plain X-ray will miss early disease.